Filter for fuel pump



Nov. 8, 1966 D. A. REISE FILTER FOR FUEL PUMP Filed Nov. 26, 1962 IIIIIIIIIIIIIlm FIG.

IN VEN TOR.

' DONALD A REISE BY AGENT FIG.4.

United States Patent 3,283,911 FILTER FOR FUEL PUMP Donald A. Reise, St. Louis, Mo., assignor to ACE Industries, Incorporated, New York, N.Y., a corporation of New Jersey Filed Nov. 26, 1962, Ser. No. 239,947 Claims. (Cl. 210-416) This invention is directed to a fuel system for internal combustion engines and particularly to means for providing a novel filtering structure for fuel in said systems.

It is normal to filter the fuel flowing from a fuel reservoir to the carburetor of an internal combustion engine to eliminate any foreign dirt particles which may be carried by the fuel to the carburetor and which would result in clogging the small passages of the carburetor and preventing its effective operation.

It is the object of this invention to provide a mesh fuel filter for the fuel systems of small carburetors and fuel pumps, which is inexpensive in fabrication.

It is a further object of this invention to provide a novel mesh fuel filter, which adapts itself to such plastic and synthetic materials utilized in fuel systems.

The novel fuel filter consists of an elliptical shaped screen which matches an angled seat in a tubular member of a fuel system. The screen may be held in place in several different ways, as, for example, by a tube pressfitted into the fuel conduit, and in which the tube has an end cut at the same angle as the angled seat. The tube is pressed into the fuel conduit and forces the screen in place in a sealing relationship to the angled seat.

FIGURE 1 discloses a fuel system for a small carburetor and incorporating the invention.

FIGURE 2 shows in section, a fuel pump structure utilized in the fuel system of FIGURE 1 and in accordance with the invention.

FIGURE 3 is a mesh screen utilized in the pump of FIGURE 2.

FIGURE 4 is a retaining tube for the mesh screen of FIGURE 2.

FIGURES 5 and 6 are alternate structures, which may be used for mounting of the novel screen of the invention in a fuel conduit.

FIGURE 1 shows a fuel system consisting of a fuel tank 10 connected by an inlet conduit 12 to the inlet fitting 14 of a fuel pump structure 16, which is mounted on the carburetor 1 8 having a flanged end 20 held by threaded studs 22 to the crankcase 24 of an engine E. The fuel pump 16 also includes an air pulse inlet fitting 26 connected by a flexible tubing 28 to an inlet fitting 38 opening into the crankcase 24 of the engine E.

The carburetor 18 consists primarily of an air filter housing 32 enclosing an air filter for providing a clean flow of air into an air and fuel mixture conduit 34 opening into the crankcase 24 of the engine E, as shown in FIGURE 1. A manually operated throttle valve 36 is mounted on a throttle valve shaft 38 for rotational movement from a closed position, shOWn in FIGURE 1, to an open position. A choke valve 40 is also rotatably mounted on a shaft 42 for manual adjustment by a choke lever 44 connected to the shaft 42, for moving the choke 40 from a wide open position, schematically shown in FIGURE 1 to a position closing the conduit 34.

The pump structure 16 is shown in detail in FIG- URE 2 and consists of a cup-shaped body 46 having a rim portion 48 snapped into a grooved rim 50 of a second body portion 52. A flexible diaphragm 54 has its periphery tightly held in a sealed relationship between the rim portions 48 and 59 of the two body structures 46 and 52 respectively. The diaphragm 54 forms, thus, an air pulsing chamber 56 in the pump body 46 and a liquid fuel pumping chamber 58 with pump body portion 52. The air inlet fitting 26 is molded with the pump body portion 46 and provides a conduit leading into the pulse chamber 56. Also, the inlet fitting 14 of the pump is molded integrally with the pump body structure 52 and provides a fuel inlet conduit 61) having a cylindrical inner wall surface. Conduit 60 leads into the pump chamber 58. An inlet check valve 62 is movably mounted within a small passage connecting with the inlet 60 with pump chamber 58. The pump body 52 also has an outlet passage 64 leading from the pump chamber 58 and adapted for friction attachment to an inlet fitting 66 of the carburetor 18. In the outlet passage 64 is mounted an outlet check valve structure 68 for controlling flow of fuel from the pump chamber to the outlet 64.

-In operation, air pulses from the crankcase 24 of the engine E are transmitted through the flexible conduit 28 and the air inlet fitting 26 to the pulse chamber 56. The pulses are both positive and negative in value and accordingly, reciprocate the diaphragm backward and forward. This provides varying pressure conditions within the pump chamber 58, which are sufficient to suck fuel through the inlet conduit 12 from the fuel tank 10 and past the inlet check valve 62 into the chamber 58. The fuel is forced by positive pulses within chamber 56 past the outlet check valve 68 and through the inlet fitting 66 to the carburetor 18.

In accordance with the invention, a mesh filter element 70 is mounted Within the fuel inlet fitting 14 of the pump structure 16. The mesh filter 70 as shown in FIGURE 3 consists of a flat mesh screen having an elongated oval shape, so that it may be fitted into the cylindrical passage 60 of fitting 14 at an angle, as shown in FIGURE 2. To retain the filter 70 within the fitting 14 there is provided a short tubular element 72, which has an outsde diameter substantially equal to the inside diameter of the inlet passage 60 so that it may be press-fitted within the passage 68. Also, passage 60 is formed with a flat annular shoulder 74 against which the filter 70 is fitted. The short retaining tube 72 has an end portion 76 terminating in a plane which is at an acute angle to the axis of the inlet fitting 14. This plane is the same as that assumed by the mesh screen 70 Within the inlet passage 60 and also parallel to the plane of the annular shoulder 74 formed in the surface of passage 60. In this manner then, by press-fitting the retaining tube 72 into passage 60 the shaped end 76 of the tube will be forced tightly against the peripheral edge of the mesh screen 70 and hold it against the shoulder 74 with suflicient force as to form a fuel-tight seal between the wall of inlet passage 61) and the periphery of screen 70.

FIGURES 5 and 6 show alternate methods of mounting the mesh screen 70 within the inlet passage 60 of the fitting 14. In place of the retaining shoulder 74 formed in the surface of inlet 60, the mesh screen may be fixed to the surface 76 of the retaining tube 70 by either brazing, welding, soldering or by any appropriate cementing means to secure the periphery of screen 70 to the end surface 76 of the tube 72. FIGURE 6 shows a pair of retaining tubes in which a tube 78 is first pressfitted into the passage 60. Retaining tube 78 has a tereminating end 80 formed at an angle to the axis of inlet passage 60 and lying in a plane substantially parallel to the plane that surface 76 of tube 72 will attain in the fitting 14'. The mesh screen 70 is then placed into the passage 60' and the retaining tube 72 is press-fitted into the fitting 14 so that its angled surface 76 will abut against the matching angled surface 80 of tube 78. The two retaining tubes 72 and 78 are pressed sufficiently tight together as to grip the peripheral edge of screen 70 between their angled ends and provide an effective fluid seal at the periphery of the screen 70.

The particular materials utilized for the mesh screens 70 and the retaining tubes 72 and 80, as well as the fuel conduits, such as the pump inlet fitting 14, may be of any appropriate material. For example, the pump of FIGURE 2 is shown made of a plastic material such as acetal resin, which readily lends itself to this particular type of structure and which can be molded with any desired configuration, such as the shoulder formation 74 within the fuel passage 60. The retaining tube 72 may be of a metal stock material such as a seamless brass tubing having the outside diameter equal to the inside diameter of the fuel passage 60, as described above. The mesh screen 83 can be of any material which lends itself to the formation of mesh, as either a plastic material or a brass mesh material.

Screen 70 may have any desired fineness, for the purposes described. For example, a brass screen having 120 mesh per square inch is of a fineness normally used for a fuel system of the type described. The retaining tubes 72 and 80 may also be of a plastic material, such as an acrylic or an acetal resin, which also can be shaped and assembled .by a friction fit into either a metal or a plastic conduit fitting 14. The cementing material in the modification of FIGURE 5, in case the retaining tube 72 and the mesh screen are of plastic, may be a solvent of the plastic material to tightly bond the periphery of screen 70 to the shaped end 76 of tube 72.

The particular application of the novel filter structure to the inlet fitting 14 of a pulse pump 16, asdescribed above and as shown in the figures is not limited to the use of this mesh screen. It is obvious that such a mesh screen may be utilized in any portion of the fuel system between the fuel reservoir and the carburetor 18. For example, the inlet fitting 66 of the carburetor may be adapted for the mounting therein of a mesh screen of oval configuration as shown in FIGURE 3 and as described above.

The mesh screen of this invention provides an effective filter arrangement which is easily assembled and with a minimum number of tools and operations. The advantage of providing an oval shaped screen 7 0 mounted at a sharp angle with the axis of the fuel passage 60, is that it provides a greater filtering surface .to the flow of fuel through the passage 66. In fact, a screen of the type described mounted within the fuel passage 60 will provide two and one-half times as much surface area, when mounted at an angle of with the axis of passage 60' than would a similar mesh screen of circular shape mounted normal to the axis of passage 60. Such a screen mounted at an angle will not clog as quickly as one of less area and thus provide greater life. Also, the mesh screen 70 placed at an angle and providing a greater number of apertures therethrough results in less resistance to fuel fiow through the passage 60, than would be provided by a similar screen of equal mesh mounted normal to the axis of passage 60.

The shape of screen 70 has been described as oval. However, the shape is not limiting to the invention. A rectangular screen may be positioned at an angle in a rectangular fuel passage in the manner described above. Other configurations are also possible. It is understood that the screen must be of the size and shape of the section of the fuel passage where the screen is mounted, so that all of the peripheral edge of the screen can be sealed to the inner wall surface of the fuel passage.

I claim:

1. The combination in a fuel pump having a pumping chamber and means forming an inlet passage communicated with said pumping chamber, filter means retained in said means forming said inlet passage and including said means forming said inlet passage being comprised of a moldab-le material, a peripheral shoulder formed on an internal wall of said means forming said inlet passage and lying in a plane disposed in an acute angle to the longitudinal axis of said passage, a planar filter screen positioned in said means forming an inlet passage and having the edge thereof peripherally coextensive with and abutting said peripheral shoulder, an elongated retaining member having open ends and being fixedly secured in said passage, and said member having one edge disposed in coextensive engagement with the periphery of said filter screen for maintaining the latter in said passage, thereby forming a liquid tight seal at said filter screen periphery.

2. In the combination as defined in claim 1 wherein said elongated retaining member extends longitudinally of said means forming said inlet passage and terminates at the inlet opening of the latter, thereby providing a uniform diameter through said means forming said passage.

3. In the combination as defined in claim 1 wherein said elongated retaining member is comprised of a meta-llic tubular element.

4. In the combination as defined in claim 1 wherein said elongated retaining member positioned at one side of said filter screen includes a center bore aligned coextensively with the portion of said means forming a passage disposed at the opposite side of said filter screen.

5. In the combination as defined in claim 1 wherein said elongated retaining member is characterized by an inside diameter slightly greater than the inside diameter of said means forming a passage for holding said retaining member closely fitted into place in said passage.

References Cited by the Examiner UNITED STATES PATENTS 504,438 9/1893 Messler 21D446 X 915,185 3/1909 Kelly 210--335 X 1,514,979 11/1924 McMillin 210-435 X 2,087,807 7/1937 Mossburg 2l0310 2,762,512 9/ 1956 Textor 2l0446 2,979,312 4/ 1961 Phillips. 3,141,048 7/ 1964 Schneider. 3,179,055 4/1965 Kalert L 10344 FOREIGN PATENTS 529,887 11/1940 Great Britain.

REUBEN FRIEDMAN, Primary Examiner.

HARRY B. THORNTON, Examiner.

F. W. MEDLEY, Assistant Examiner. 

1. THE COMBINATION IN A FUEL PUMP HAVING A PUMPING CHAMBER AND MEANS FORMING AN INLET PASSAGE COMMUNICATED WITH SAID PUMPING CHAMBER, FILTER MEANS RETAINED IN SAID MEANS FORMING SAID INLET PASSAGE AND INCLUDING SAID MEANS FORMING SAID INLET PASSAGE BEING COMPRISED OF A MOLDABLE MATERIAL, A PERIPHERAL SHOULDER FORMED ON AN INTERNAL WALL OF SAID MEANS FORMING SAID INLET PASSAGE AND LYING IN A PLANE DISPOSED IN AN ACUATE ANGLE TO THE LONGITUDINAL AXIS OF SAID PASSAGE, A PLANAR FILTER SCREEN POSITIONED IN SAID MEANS FORMING AN INLET PASSAGE AND HAVING THE EDGE THEREOF PERIPHERALLY COEXTENSIVE WITH AND ABUTTING SAID PERIPHERAL SHOULDER, AN ELONGATED RETAINING MEMBER HAVING OPEN ENDS AND BEING FIXEDLY SECURED IN SAID PASSAGE, AND SAID MEMBER HAVING ONE EDGE DISPOSED IN COEXTENSIVE ENGAGEMENT WITH THE PERIPHERY OF SAID FILTER SCREEN FOR MAINTAINING THE LATTER IN SAID PASSAGE, THEREBY FORMING A LIQUID TIGHT SEAL AT SAID FILTER SCREEN PERIPHERY. 